Various types of steering railway trucks have been proposed wherein the angular positions of the axles and their associated wheels are allowed, or forced, to adjust during curve negotiation to maintain more or less radial positions with respect to the curve. Such arrangements are generally proposed to reduce friction and wear of the wheels and rails by minimizing lateral creep forces. The use of such trucks has been considered both for nonpowered railway cars and for locomotives with motorized axles.
An extended discussion of one such railway truck, intended primary for locomotive application, may be found in U.S. Pat. No. 4,628,824 issued Dec. 16, 1986 to the assignee of the present invention. This patent also contains an extensive list of prior art references. United States patents and applications setting forth additional features for self-steering railway trucks for use with locomotives and the like include U.S. Pat. Nos. 4,679,506 and 4,679,507, both issued July 14, 1987 and application Ser. No. 010,365 filed Feb. 3, 1987, all assigned to the assignee of the present invention.
U.S. Pat. No. 4,679,506 discloses an arrangement for powered three axle self-steering railway locomotive trucks. All axles are motorized and a steering beam pivoted on the frame is utilized as part of a linkage to interconnect the end axles for self-steering yaw motions of opposite sense and equal extent. This arrangement, together with those of U.S. Pat. No. 4,628,824 and application No. 010,365 may be considered as representing earlier arrangements in the development of the present invention.